Electric pneumatic switch.



J. DESMGND.

ELECTRIC PNEUMATG SWITCH.

APPLICATION FILED JULY 17,1911.l

f5 Patented Feb. 18, 1913.

i a. "tra tij kiln si.. lthltr in Je; dit

Fell-*TENT tlllltlllil.

JOHN EESMGND, Ol? CHCAG,

XLLINOIS ELECTRIC PNEUMATIC SWITCH.

Application ined my i7,

TOEN whom if may concern:

Be it known that l, donn nsncxn, a citizen of the United States, residing at Chicago, in the county of Cook and State of illinois, have invented certain new and useful improvements in Electric Pneumatic Switches, of which the ollowing is a speciication.

illy invention relates to improvements iin electric switc es, and has more particular reference to switches that are adapted to he aiit-f rnatically operated as a result of a change oi pressure Within a container' with which it may he associated.

@ne of the objects of my invention is to provide in a switch ot the character to he describe-d, means .tor producing a quick, arcavoiding hrealibetween the members of an electric switch at a critical point with reference to the rise of pressure to which a receptacle may he subjected, and means for adjust-ing the operating mechanism, with reterence to the pressure to he carried in the container, whereby a higher or lower pres-l sure may be maintained therein, through the controlling agency of the switch exercised upon the pressure-producing medium.

Another object ot' my invention is to provide an electric switch of this general character that is operable independent of the electric current, whether alternating or direct in character, and to some extent regardless of the electric difference of potential at the switch terminals,

Other and further objects of my invention will become readily apparent from a consideration of the following description taken in conjunction with the drawings, wherein- Figurc l 'is a vertical elevation of the device'; Fig. 2 is a cent-ral sect-ion of the same; Fig. 3 is a section taken on line 3I ot Fin, 1;-lt`ig. el is a. section taken on 'line -l--nl o'l` Fig. 2; and Fig. 5 is a section taken on line of Fig. 2.

ln all of the views, the saine reference characters indicate similar parts.

A diaphragm casing lt) composed ol' two parts. ll and l2, upper andlowcr part.`l rcspectirely. secured together h v a series ol* screws 13. The parts nrc counter-bored to provide space for movement oil a pressureresponsire diaphragm 14. The diaphragm is clamped hetween'the casing parts at its periphery and is centrally perforated. ln the central perforation is secured a verti- Spccncation of Letters Patent.

Patented lteh. i8, il. 1911. serial No. essen.

cally extending nozzle l5 provided with an internal valve seat, as at 16, where the two diameters l? and ld conjoin. stein 19 is provided with a head 20, that rests upon an` adjustable plug 21. The plug is screwthreaded and is vertically adjust-able Within the integral perforated huh 22. It is perforated axially, as at 23, to permit tree pas sage of air or other fluid to the under side of the diaphragm from the container (not shown) to which it may he attached. rllhe stein t9 is heldlwith its head 20 against the pluga 2l by means of a light helical open spring Q4, one end of which rests against the lower surface oi the diaphragm and the other on the plug 2l. rlhe upper end 25 of the stem is a valve that seats tightly in the valve seat 16 and closes communication with thcbore 1S when the parts are in Lche positions shown, as when the pressure is low. W hen the pressure reaches the critical point atwhich it is desired that the electric switch shall he opened, the diaphragm will `loe raised, thus moving the nozzle l5 so as to carry the valve seatJ 1G above the valve 25. thus permitting the air to pass into the bore 18. A

The switch parts and their operation Will now he described. 1

lhe nozzle is screw-threaded at its upper end, as at Q6, upon which is supported the entire switch mechanism. A casing or cylinder QT has screw-threaded engagement with, and is supported on, the end 26 and contains a hollow plug or piston 28 that moves freely, but tits snugly in the bore thereof. A screw-threaded cap 29, overlies the upper end of thc casing 27 and provides :xn upwardly projecting screw threaded .stein guide 30. Upon this guide a permanentinagnet 3l is supported. The magnet` is perforated through, its yoke and the perforation is threaded for engagement with the guide 30. the salient poles ofthe magnet being turned upwardly. To the legsY or poles ot' the magnet 3l is secured a disk 32 of insulating' material, perforated for receiving the legs ol'l the magnet. The disk 3Q carries t wo plates of conducting material, 33 and 3l, such as brass, copper, or the like, to which the switch terminals 35 and 3G are connected l l respectively. A stein 37 passes treely through the guide 30 into the interiol of the hollow piston 28, and has a head 58 that normally rests upon the interior bottom of said piston. .An open helical spring 39 surrounds the stern 37 and rests upon the head thereof, the upper end abutting against the inner surface of the cap 27. The spring serves to hold the stem 3T in its contact with the piston. The upper end ot the stem l? is screw-threaded, at 10, and carries, between the nuts l1 and 42 an armature f4.3. composed of a disk of iron or other material, susceptible of magnetic induction, and which in the position shown closes the magnetic circuit ot' the permcuent magnet 3l.

Superposed 'above the dish 3 and surn rounding the stem 3T is a disk lll thatl carries an anuulus or ring 45 oi electrically conducting material shown in the drawing as carbon. rlhisring, in the position shown, rests upon the conducting plates 33 and 3l, and thus closes the electric circuit between the switch terminals 35 and "When the ring is lifted above these plates, the switch is thereby opened.

ils an illustrative example of the adaptability and use of my switch, l' will. assume that the switch terminals 35 and 36 are ineluded in circuit with an electric motor and the motor is arranged to operate a pump to pump air into a container with which the part 22 is connected; and that it is desirable to maintain the air pressure in said container at. a predetermined value. lllhen the pressure reaches approximately that point, the diaphragm llwill be raised and permit air to pass into the casing 2?, through the bore l and under the piston 9S. lt will be observed that the stem 37 is held depressed by the permanent 'magnet 3l and its cooperating armature i3 and therefore the ring Ll5 cannot be moved upwardly and away from the Contact plates 33 and 84 until the portative ctlect olf the magnet has been overcome and then itvvill. move quickly, thereby producing a quick break between the switch electrodes. The pressure operating upon the piston 28 will raise it in the casing or cylinder 27 and thereby lift the stem 3? and armature 43, overcoming the magnetic adhesion and causing the ring 45 to be moved upwardly quickly.

lo vary the operation of the device with reference to the air pressure, l provide an open helical sprino` -l which surrounds the nozzle l5 and rests upon the diaphragm 1st,

thetension of which may be varied by turning the cap L17. The cap 47 is in position, as shown, to/cause the spring l5 to exert its greatest pressure upon the diaphragm.

l/Vhen the valve 28 is raised, as described, its open end rca-ts upon the valve seat 48, thereby [nfoviding a seal to prevent leak around the stem 3i", and when the pressure in 'the container is below normal, the valve provides a sealingmeans.

rllhe circuit is broken at points Within the fields of the permanent magnet and thereincassi.

fore the magnet exercises the dual function of' holding the switch closed and causing a quick movement when it is opened and "blowing out the arc or preventing the formation ol arcs at the points et separation oir the :switch members.'

lli'hilc l have herein disclosed a part-ica lar cnribodimcnty of my invention, it is evident that considerable change can be made in the structure illustrated within the scope of the appended claims, without departure 2. In a device of the character described,.

a. permanent. magnet, au insulating block secured thereto, separated contacts on said insulating block, one adjacent each pole et' the magnet, an armature spanning the poles of the magnet, and a movable contact secured to said armature and spanning said' contacts.

In a device of the character described, a. circular insulating block, a magnet secured in the center thereof, contacts on diametrically opposite sides of said block, each extending near a pole of said magnet, a. ring-shaped movable contact to connect said contacts, and an armature mounted within said ring-shaped contact for coaction Wit-h the magnet.

t. In a device ot' 'the character described, a centrally perforated diaphragm arranged to receive pressure upon one side thereof, a

switch, a pressure-responsive device for opening the switch, and a valve operable by said diaphragm to open and close the passage through said perforation therein for control of said pressure-responsive device.

5. In a device oit the character described, for connection to a. source of pressure supply, a centrally perforated diaphragm, a switch, a. sivitch-opening pressure-responsive deviee, a valve normally closing a path from the pressure side`ot the diaphragm to the pressure-rcsponsive device through the perforation in said diaphragm, one member of said valve being connected to said dia phragm for movement therewith to open said path.

6. ln a device et the-character described, a diaphragm having a central perforation, a. valve member extending through said perforation, a coacting valve member carried `by the diaphragm, a switch, and a switch opening pressure responsive device associated with said valve for operation upon openingthereof.

weasel 7. in a device of the character described, a diaphragm having a central perforation, a Valve member extending through said perforation, a coaching valve member carried by the diaphragm, a switch, a switch-opening pressure-responsive device associated with said valve for operation upon opening thereof, and means to vary the projection of Said irst mentioned Valve the perforation in the diaphragm.

8. In a device of the character described, a diaphragm having a central perforation, a valve member extending through said per foration, a eoacting valve member carried by the diaphragm, a switch, a switch-open mg pressure-responsive device associated with said valve for operation upon opening thereof, a cap guldingiy surroundlng the member through upper end of said diaphragmparried vaive member, and a spring between said cap and diaphragm 'to determine the critical res# sure neceeeary to cause waive-opening movement of said diaphragm.

9. In a device of the character described, a pressure-rponeive diaphragm, an electric switch superposed thereon and supported thereby, and diaphragm-controiied means between said diaphragm and switch for operating said switch.

In testimon f whereof hereunto eet m 30 hand in he presence of two Witnesses.

JHN DESMGND. In the presence of- W. LINN ALLEN, MARY F. ALLEN. 

